Botulinum Toxin for the Treatment of Chronic Pain Syndromes

M. D. Anderson Cancer Center
Cancer Newsline Audio Podcast Series
Date: April 20, 2009
Duration: 0 / 10:13

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Lisa Garvin:

Welcome to Cancer Newsline, a weekly podcast series from the University of Texas M. D. Anderson Cancer Center.  Cancer Newsline helps you stay current with the news on cancer research, diagnosis, treatment, and prevention, providing the latest information on reducing your family’s cancer risk.  I’m your host, Lisa Garvin.  Today, we’re talking with Ankit Patel, MD, he’s a chronic pain management fellow, here at MD Anderson, and we’ll be talking about botox or botulinum toxin. Welcome.

Ankit Patel, MD:

Thank you for having me.

Garvin:

Let’s talk about botulinum toxin.  Of course, we knew it twenty, thirty years ago as the nasty poison you found in old can goods.  How did that become a medical therapy?

Dr. Patel:

It’s a fascinating chemical and scientists have found a way to harvest its effects on the human body and target it toward certain treatments.  It’s come a long way.

Garvin:

And it’s a paralytic and when they use it for cosmetic surgery doesn’t it paralyze the nerves or muscles?  What is its action?

Dr. Patel:

Sure, the way botulinum toxin works is, and I’ll keep it termed that way instead of botox ‘cause there’s various brands out there, is that chemically it inhibits the release of certain chemicals where your nerves and muscles meet.  And so, the signal to transmit the muscle contraction is decreased by this chemical.

Garvin:

How does that work with chronic pain?  How did it make the leap from a cosmetic drug to a pain drug?

Dr. Patel:

It’s not just a cosmetic drug, although that’s just one of its FDA approved indications.  There are certain involuntary neurological conditions involving muscle contraction that it’s used for.  And, some studies early on showed that in these patients with these muscle contractions, they were actually getting pain relief; even before the onset of action of the muscle contractions.  So, people started thinking hey, this has properties beyond just inhibiting that muscle contraction; and that’s where the leap took place for pain management.

Garvin:

How is it used for chronic, or how long has it been used for chronic pain.  This is a fairly emerging use for this.

Dr. Patel:

Yeah, again this is all off-label use and people are studying it in the community.  And, it’s really come about by looking at its effect in rats, animals, as well as in the laboratory.  They found that the chemical, botulinum toxin inhibits release of some pain mediators involved in our normal pain cascade.

Garvin:

So you did say it was off-label use, so it is not FDA approved.

Dr. Patel:

That’s correct.  It’s not first line treatment for any pain syndromes yet.  Every day there are new and differential diagnosis and items that it is being investigated into.  But it’s still not the mainstream of pain management.

Garvin:

How is it being used here at M. D. Anderson?  What sort of candidates are you considering for botulinum toxin?

Dr. Patel:

Several services use botulinum toxin.  The most common used diagnosis are for FDA approved indications.  So, if a patient has a stroke or a tumor in the brain that leads to spasticity then there are certain indications that it can be used for; such as around the neck called cervical dystonia.  There are several patients that are getting treatment for FDA off-label uses but that’s because they have tried all other conservative options and other causes have been ruled out for their pain problems.

Garvin:

So botulinum toxin, here at M. D. Anderson, is used when other things like fentanyl and morphine and your typical pain reliefs fail?

Dr. Patel:

It depends on the individual patient.  So, in pain management we try to reverse any underlying problems of their pain.  For example, if someone has intractable muscle pain, secondary to a muscle spasm or myofascial pain, we try to use a multi-disciplinary treatment approach involving physical therapy, various medications and other more approved indications for the management of that pain.  If they’ve failed those courses only then would we consider something like botulinum toxin.

Garvin:

And how is it administered?  I assume it’s an injection.

Dr. Patel:

Yes, it’s administered via an injection into the muscle that you want to target.

Garvin:

Are the effects immediate, is it something that’s cumulative, or…?

Dr. Patel:

That’s a good question.  We try not to tell our patients to look for an effect right away because the mechanism states that it will take a few days to take effect.  And it’s not a permanent effect as well.  It takes several months to get a good peak effect as well as it comes off three to four months after its injected.  So, some patients do need repeat injections.

Garvin:

So it’s a single injection at first.

Dr. Patel:

That’s correct, if it’s in a single muscle.  There are certain cases where several muscles may be involved, so you may inject several sites.  This is why I still think it’s not completely FDA approved.  There’s a lot more research that needs to be done as far as how many muscles to inject, what’s the adequate dose, what combination of treatments are useful.  I would say the use of this chemical for pain is still in its infancy.

Garvin:

Do you use it in large muscles only or can it be used in any muscle in the body?

Dr. Patel:

It can be typically used in any muscle in the body and there are even urologists looking at the affect of this chemical for certain bladder wall problems as well.  So, it’s not limited to just skeletal muscle like on the body but in typical pain management world the off-label use involves typical skeletal muscles around the shoulders, around your spine, around your scapula that fall into certain diseases such as myofascial pain syndrome.

Garvin:

What sort of cancers or what types of cancers would we see this sort of myofascial pain?

Dr. Patel:

That’s a great question, and I wouldn’t be able to give you the answer to that because these kinds of pain syndromes are not necessarily related to a particular cancer.  You know, cancer itself can cause pain and the treatment of the cancer can itself cause pain such as chemotherapy or radiation induced pain, but botulinum toxin is not targeted at cancer pain specifically, it’s typically targeted at certain neurologic conditions or pain from muscular skeletal causes that the cancer pain may just so happen to have.

Garvin:

I know you recently gave a talk in the Pain Grand Rounds, here at M. D. Anderson about botulinium toxin and pain.  You’re basing your experience here, I would guess.  So, how many patients have you treated and what sort of responses have you seen?

Dr. Patel:

Sure, most of my experience actually comes from training.  My background is Physiatry, and we use botulinum toxin in non-cancer patients, such as patients with traumatic brain injuries or spinal cord injuries and various muscle skeletal problems.  At M. D. Anderson again, there is very limited patients that we’ve used it on.

Garvin:

Do you hope to do some research?  Are there any protocols open at this point?  Or, where are we going from here, I guess?

Dr. Patel:

Um, I think at this time there’s no research protocols or studies investigating botulinum toxin for pain.  In the future, I suspect there will be; however, I think there still needs to be more literature before we take that next step here at M. D. Anderson, especially because its use in pain is still off-label and it’s primarily for muscular skeletal conditions that are not necessarily within the cancer pain patient.

Garvin:

In the field of cancer pain management are we looking at more non-opioid therapies, such as botulinum toxin?

Dr. Patel:

Um, I think a generalized statement would be accurate that when you manage a cancer pain patient you want to provide a multi-disciplinary, all encompassing approach because the pain is very complex, it may be from the primary cancer, the treatment of the cancer, or pain that’s not cancer related.  So, I think botulinum toxin would fit into that third category of not necessarily cancer related pain, and its off-label use so I think it would be incorporated into the whole picture once patients have been ruled out for any other reversible causes, recurrences of disease and other more conservative treatment approaches have been tried.

Garvin:

And as a fellow, you said you got interested in botulinum toxin through training, but how did you kind of fall into investigating it as a pain medication?

Dr. Patel:

I found it just very exciting as a drug that’s going to continue to change the way we manage pain.  Pain management is an ever changing field as it is, but on top of that a chemical that we still don’t know exactly how it works and continue to learn more about every day, is to me very exciting.

Garvin:

‘Cause I know, or at least at this point, I think that opioids are the standard of care things like morphine and so forth but it sounds like its expanding so you’re getting more options out there that you can look at.

Dr. Patel:

Within the medication treatment aspect of pain management we try to, again, treat the underlying problem and consider injections where it’s appropriate.  As well as using a combination of opioids, if necessary, in the short term, as well as adjuvant medications like nerve pain medications, or muscle relaxants, anti-inflamatories where they are indicated.

Garvin:

I think that covers it all.  Are there any final thoughts that we may have missed or is there a take home message for our audience?

Dr. Patel:

I think the best take home message for our cancer community as well as non-cancer community is that botulinum toxin is a fascinating chemical and I think that we’re going to see more regarding its use in pain in the future.  It’s still in its infancy, I would say is the take home message and I wouldn’t advocate it being used on a regular basis because it’s still off-label, but it’s a very exciting drug that should be used in particular muscular skeletal conditions when other treatment options have been tried.  And, even when it is used, it should be used in a combination with other treatment approaches to maximize its outcomes.

Garvin:

Great.  Thank you, Dr. Patel for joining us today.

Dr. Patel:

My pleasure, thanks for having me.

Garvin:

If you have questions about anything you’ve heard today, on Cancer Newsline, contact askMDAnderson at 1-877-MDA-6789 or online at www.mdanderson.org/ask.  Thank you for listening to this episode of Cancer Newsline, tune in next week for the next podcast in our series.

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